Model data of a three-dimensional object arranged in a three-dimensional virtual space corresponding to a real space is displayed in such a manner that the model data is overlaid on a captured image taken by an imaging device. This technology expands information collected through human perception, such as visual perception, and thus is called augmented reality (AR) technology, for example. The model data of a three-dimensional object arranged in a three-dimensional virtual space corresponding to the real space is called AR content. Note that model data of a three-dimensional object is also called an object.
AR content is information in which it is defined in advance what kind of object is to be arranged in what attitude at what position in a three-dimensional space. Accordingly, with AR technology, a projection image of an AR object may be generated based on arrangement defined in advance, and the projection image may be displayed in such a manner as to be overlaid on a captured image. Note that a projection image of an AR object is generated based on the positional relationship between an imaging device and an AR content.
In order to determine the positional relationship between an imaging device and an AR content, a reference object is used. For example, it is typical to use an AR marker as a reference object. That is, when an AR marker is detected from a captured image taken by an imaging device, the positional relationship between the AR marker and the imaging device is determined based on a figure of the AR marker that appears in the captured image of the imaging device. Then, reflecting the positional relationship, a projection image of the object of AR content associated with the AR marker is generated, and that projection image is displayed in such a manner that it is overlaid on the captured image (for example, Japanese National Publication of International Patent Application No. 2010-531089, International Publication Pamphlet No. WO 2005-119539).
Here, in order to display the AR content in such a manner as to be overlaid on the captured image, operations of creating AR content (also referred to as authoring) have to be performed in advance. Note that the operations of creating AR content are operations that generate an object and set information on arrangement of that object in a three-dimensional space. Note that the information on arrangement is a relative position and an attitude when measured with respect to the reference object.
Here, there is an information processing device that arranges a virtual object at a three-dimensional position corresponding to a designated position designated by the user on a plane including a face, which is a face of an object model in the real space reflected in an input image and is designated by the user (Japanese Laid-open Patent Publication No. 2012-168798). That is, the information processing device may arrange a virtual object on the plane of the object model existing in the real space in accordance with the user's instruction for the designated position.